Grafted organopolysiloxanes prepared by reacting olefinic monomers with organopolysiloxanes to form tough coating compositions, paper release compositions, lubricants, sealants, and the like are known and described in such patents as U.S. Pat. No. 3,430,252 and U.S. Pat. No. 3,565,851 (Neuroth), U.S. Pat. No. 3,631,087 and U.S. Pat. No. 3,694,478 (Adams et al.), U.S. Pat. No. 2,958,707 (Warrick), and U.S. Pat. No. 4,166,078 and U.S. Pat. No. 4,172,101 (Getson), all of which are hereby incorporated by reference.
It has now been discovered that a class of organopolysiloxanes grafted with C.sub.2 -C.sub.3 unsaturated fluorocarbons, such as vinylidene fluoride (CH.sub.2 .dbd.CF.sub.2), can be combined with a vinyl-containing crosslinking agent and a free-radical initiator to form a curable composition having a unique range of properties, depending on the amount of fluorocarbon grafting. After curing, polymeric materials varying in forms from thermoplastic to elastomeric, and having improved mechanical properties and solvent resistance, are obtained.